python实现八皇后问题

import random

def judge(state, nextX):   #判断是否和之前的皇后状态有冲突
    nextY = len(state)
    for i in range(nextY):
        if abs(state[i]-nextX) in (0,nextY-i):
            return True
    return False

def queens(num = 8, state = ()):
    for pos in range(num):
        if not judge(state, pos):
            if len(state) == num-1:
                yield (pos,)   #(pos,)中的逗号使其必须被设置为元组而不是简单地加上括号
            else:
                for result in queens(num, state+(pos,)):
                    yield (pos,)+result

def randomPrint(solution):
    for i in range(8):
        print( '•'*solution[i]+'X'+'•'*(8-solution[i]-1))

ans = int(len(list(queens(8))))
print(ans)
randomPrint(random.choice(list(queens())))  #随机输出一种情况